MIPS: Clean up MIPSxx-optimized bitop functions

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 76 insertions, 38 deletions

diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index 49df8c4c9d25..bac4a960b24c 100644
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -558,39 +558,67 @@ static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *
         __clear_bit(nr, addr);
 }
 
-#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
-
 /*
  * Return the bit position (0..63) of the most significant 1 bit in a word
  * Returns -1 if no 1 bit exists
  */
-static inline unsigned long __fls(unsigned long x)
+static inline unsigned long __fls(unsigned long word)
 {
-        int lz;
+        int num;
 
-        if (sizeof(x) == 4) {
+        if (BITS_PER_LONG == 32 &&
+            __builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r) {
                 __asm__(
                 "       .set    push                                    \n"
                 "       .set    mips32                                  \n"
                 "       clz     %0, %1                                  \n"
                 "       .set    pop                                     \n"
-                : "=r" (lz)
-                : "r" (x));
+                : "=r" (num)
+                : "r" (word));
 
-                return 31 - lz;
+                return 31 - num;
         }
 
-        BUG_ON(sizeof(x) != 8);
+        if (BITS_PER_LONG == 64 &&
+            __builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
+                __asm__(
+                "       .set    push                                    \n"
+                "       .set    mips64                                  \n"
+                "       dclz    %0, %1                                  \n"
+                "       .set    pop                                     \n"
+                : "=r" (num)
+                : "r" (word));
 
-        __asm__(
-        "       .set    push                                            \n"
-        "       .set    mips64                                          \n"
-        "       dclz    %0, %1                                          \n"
-        "       .set    pop                                             \n"
-        : "=r" (lz)
-        : "r" (x));
+                return 63 - num;
+        }
+
+        num = BITS_PER_LONG - 1;
 
-        return 63 - lz;
+#if BITS_PER_LONG == 64
+        if (!(word & (~0ul << 32))) {
+                num -= 32;
+                word <<= 32;
+        }
+#endif
+        if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
+                num -= 16;
+                word <<= 16;
+        }
+        if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
+                num -= 8;
+                word <<= 8;
+        }
+        if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
+                num -= 4;
+                word <<= 4;
+        }
+        if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
+                num -= 2;
+                word <<= 2;
+        }
+        if (!(word & (~0ul << (BITS_PER_LONG-1))))
+                num -= 1;
+        return num;
 }
 
 /*
@@ -612,23 +640,43 @@ static inline unsigned long __ffs(unsigned long word)
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static inline int fls(int word)
+static inline int fls(int x)
 {
-        __asm__("clz %0, %1" : "=r" (word) : "r" (word));
+        int r;
 
-        return 32 - word;
-}
+        if (__builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r) {
+                __asm__("clz %0, %1" : "=r" (x) : "r" (x));
 
-#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPS64)
-static inline int fls64(__u64 word)
-{
-        __asm__("dclz %0, %1" : "=r" (word) : "r" (word));
+                return 32 - x;
+        }
 
-        return 64 - word;
+        r = 32;
+        if (!x)
+                return 0;
+        if (!(x & 0xffff0000u)) {
+                x <<= 16;
+                r -= 16;
+        }
+        if (!(x & 0xff000000u)) {
+                x <<= 8;
+                r -= 8;
+        }
+        if (!(x & 0xf0000000u)) {
+                x <<= 4;
+                r -= 4;
+        }
+        if (!(x & 0xc0000000u)) {
+                x <<= 2;
+                r -= 2;
+        }
+        if (!(x & 0x80000000u)) {
+                x <<= 1;
+                r -= 1;
+        }
+        return r;
 }
-#else
+
 #include <asm-generic/bitops/fls64.h>
-#endif
 
 /*
  * ffs - find first bit set.
@@ -646,16 +694,6 @@ static inline int ffs(int word)
         return fls(word & -word);
 }
 
-#else
-
-#include <asm-generic/bitops/__ffs.h>
-#include <asm-generic/bitops/__fls.h>
-#include <asm-generic/bitops/ffs.h>
-#include <asm-generic/bitops/fls.h>
-#include <asm-generic/bitops/fls64.h>
-
-#endif /*defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64) */
-
 #include <asm-generic/bitops/ffz.h>
 #include <asm-generic/bitops/find.h>